Apparatus for making manholes of concrete

ABSTRACT

A manhole base is a concrete or like structure of cup shape, having usually a cylindrical upright wall and a bottom wall, and the inventive apparatus features a core-jacket-pallet structure in which no inversion of any of the components is involved because the core is received within the jacket from above and is spaced above the pallet at the bottom of the jacket so that concrete introduced into the annular space from above flows across the bottom space and forms the bottom wall of the manhole integrally with the annular wall.

United States Patent [191 Schmidgall 1 APPARATUS FOR MAKING MANHOLES OF CONCRETE [76] Inventor: Hertzell H. Schmidgall, Mediapolis,

Iowa 52637 22 Filed: May 21,1973

21 Appl. No.: 362,367

[52] US. Cl. 249/144 [51] Int. Cl. B220 9/24 [58] Field of Search. 425/421, DIG. 117, DIG. 126; 249/100,144,149,l51,163,178,1,11,12, 32,177,122,160,165,169,119,125,126, 173,184, 63, 67,112,141,145

[56] References Cited UNITED STATES PATENTS 788,581 2/1905 Conger 249/141 981,267 l/l911 Howard 249/144 1,665,650 4/1928 Wood 249/144 X 1,720,503 7/1929 249/144 X 2,276,558 3/1942 249/141 X 2,534,011 12/1950 Frye 108/55 X [4 1 Jan. 14,1975

2,683,298 7/1954 Fadden 249/149 X 2,894,671 7/1959 Nicholls 108/55 X 2,948,044 8/1960 Dawson 425/D1G. 117 3,142,234 7/1964 Maloon 52/19 3,159,111 12/1964 Gutridge 248/361 R 3,166,817 1/1965 Cordova 249/63 3,542,327 11/1970 Herzog 249/160 X Primary Examiner-Francis S. Husar Assistant Examiner-John S. Brown [57] ABSTRACT A manhole base is a concrete or like structure of cup shape, having usually a cylindrical upright wall and a bottom wall, and the inventive apparatus features a core-jacket-pallet structure in which no inversion of 1 7 Claims, 18 Drawing Figures PAIENTEBJAn-Mms 3.860214 SHEH 1 OF 2 BELL 155.5. EE13 Fi .5; E; E

SHEET 2 OF 2 PATENTED JAN 1 4 I975 APPARATUS FOR MAKING MANHOLES OF CONCRETE BACKGROUND OF THE INVENTION The manufacture of manhole bases differs from that of ordinary concrete pipe because the pipe has no end closure or wall and thus the pouring, setting and stripping of the jacket and core present only minor problems. The manhole base, however, necessarily having an end or bottom wall, does not lend itself readily to pipe manufacturing methods because the end wall precludes simple stripping of the form components unless an inversion step is introduced. That is, according to one known method, the core, jacket and pallet are set up and located relative to each other with an annular space between the core and jacket and a bottom space between the core bottom and the pallet. This assembly is then inverted to place the bottom space at the top; the assembly is then supported on another pallet by the former top end of the jacket; and the former pallet is removed so that concrete may be poured in from the top. The now filled form is covered to confine the bottom wall concrete" to its position and the form again inverted, after which the core may be withdrawn upwardly and the jacket subsequently stripped upwardly.

The foregoing may be traceable to the use of overhead lifts and the like, but, in any event, former systems have followed the same general pattern. Of course, the assembly, after being first inverted and poured, could be allowed to set and cure long enough to attach a lift to the manhole itself and pull it upwardly from the jacket and core, but this would tie up the jacket and core during curing and would require several jackets and cores. By use of the second inversion step, the form components may be stripped from the product and can be used over and over for the making of additional products while the products remain supported on their pallets, it being clear that pallets are relatively inexpensive compared to jackets and cores.

SUMMARY OF THE INVENTION In the present case, all inversion steps are eliminated and one jacket and one core may be used successively with several pallets for making several products. Essentially, the first step is to place on a pallet a wire reenforcing cage of conventional nature. The core is then introduced from above and centrally of the cage. The core has hollow or tubular spacer means at its bottom which contact the pallet from above and this spacer means has such height as to space the pallet and core bottom apart according to the desired thickness of the bottom of the product to be cast. Locking means carried by the core extends through and is at least partially enclosed by the tubular spacer means and is operative to lock the core to the pallet. The assembly thus far is then shifted to another station and introduced downwardly into a jacket of such diameter relative to the core as to afford an annular space defining the thickness of the upright annular wall of the product to be cast.

The structure is then filled from above with concrete, which flows transversely across the bottom space as well as filling the annular space. Any air trapped in the bottom space is vented through a controllable vent in the bottom of the core, which opening is closed subsequently to prevent concrete from entering the interior of thecore. After the usual compacting operationsnormally by use of vibrators-and the application of a top ring or header to define an annular rib on the open end of the manhole, the pallet, core and product are withdrawn or stripped upwardly from the jacket, during which time the core remains locked to the pallet, and the pallet supports the product from below. Subsequently, the top ring and pallet are secured together and, after the lock means is released, the core is withdrawn from above, leaving the product supported on the pallet, and the jacket and core may be used over and over with further pallets to make further products. Of course, when the core is withdrawn from the product, it leaves an opening in the, bottom wall because of the withdrawal of the tubular spacer means but this opening is easily and quickly filled manually.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows the step of placing a reenforcing cage on a pallet.

FIG. 2 shows the next step in which the core is introduced centrally within the cage and locked to the pallet with its bottom spaced above the pallet.

FIG. 3 shows the step of lowering the core, cage and pallet into a jacket.

FIG. 4 shows the filling or pouring step.

FIG. 5 shows the heading step.

FIG. 6 shows the step of withdrawing the core, pallet and product upwardly from the jacket.

FIG. 7 shows the step involving securing the top ring or header to the pallet while the core is withdrawn upwardly after the lock means has been released.

FIG. 8 is an enlarged sectional view of a tubular spacer means.

FIG. 9 is a view, on the same scale, of the opening in the pallet.

FIG. 10 is a view, on the same scale, ofa locking shaft and arm.

FIG. 11 is a top view of the components shown in FIGS. 8, 9 and 10.

FIG. 12 is a view, on the scale of FIGS. 8-11, showing how the bottom wall hole is filled or closed with concrete.

FIG. 13 is a top plan view of the pallet on a scale double that of FIGS. 1-7.

FIG. 14 is a top view of the core, with portions broken away.

FIG. 15 is an enlarged fragmentary sectional view on the line 15-15 of FIG. 14.

FIG. 16 is a fragmentary sectional view on the scale of FIGS. 8-12 as seen along the line 16-16 of FIG. 14.

FIG. 17 is a view similar to FIG. 11 but showing a lock arm in locked position.

FIG. 18 is a fragmentary view showing the support of the lock control shaft in the top of the core.

DESCRIPTION OF A PREFERRED EMBODIMENT FIGS. l-7 will be briefly described to explain the basic system. In these drawings, a conventional (here circular) pallet 20 is supported by the ground, floor, etc., and has centrally placed on it a typical cylindrical wire reenforcing cage 22 which is provided with a circular ring 24 for forming an ultimate hole in the side or annular wall of the manhole base to be formed. Several rings may be used according to the number of holes desired in the final product. The use of cages is of course well known. See for example the US. Pat. No. 3,440,792 to Schmidgall.

As is customary, the various steps may be performed at stations, but these details are not material here. Suffice it to say that a hollow core 26 is lowered from overhead into the cage and substantially centered therein. This core has hollow or tubular spacer means, here taking the form of three upright tubular members 28 equally spaced angularly about the axis of the core. The height of each member 28 accords with the desired thickness of the bottom wall to be formed in the final product and accordingly there is afforded a transverse bottom space 30. The top of the core may be provided with a ring 32 for connection to any suitable hoist medium 34.

As will be described later, the pallet 20 has a plurality of openings, each alined with a respective member 28, and lock means, also to be described later, is operative to lock the core to the pallet. At this point, the assembly of core, pallet and cage is lifted and then lowered into ajacket 36, which may be anchored to the ground, floor etc., in an upright position. The jacket has adjacent to its lower end stop means 38 on which the pallet ultimately comes to rest (FIG. 4). The relative diameters of the pallet and jacket are such that the pallet tolerably fits the jacket. The locking means includes means for locating or centering the pallet, core and jacket relative to each other and there is thus afforded an annular space 40 between the interior of the jacket and the exterior of the core, the thickness of which determines the thickness of the annular wall of the final product. Preferably the cage 22 is centrally of this space.

When the system has attained its FIG. 4 stage, pouring of concrete is begun and finished. The concrete flows across the bottom space 30 and, because this space is in annular or peripheral communication with the annular or peripheral space 40, the product bottom wall, as at 42, becomes integral with the product annular wall 44. After filling to the required height, the structure has applied thereto an annular header or top ring 46 to provide on the top or open end of the product an annular rib or tongue (FIG. 5). Rings of this type are conventional. See for example the U.S. Pat. No. 2,823,439 to Schmidgall.

Again according to known practice, the form and product are compacted, usually by known vibration techniques, and at a predetermined stage the product, core and pallet are stripped or removed upwardly from the jacket (FIG. 6). Again an overhead lift may be used, but the stripping may be assisted by expansion of an air bellows 48. After stripping from the jacket, the core, product and pallet assume the condition of FIG. 7 as supplemented by a plurality of vertical forceexerting means 50 which temporarily interconnect the pallet and header or ring 46. The finished product is now resting on the pallet and, following release of thelock means between the core and pallet, the core is withdrawn upwardly. Later, the means 50 are removed, along with the header 46, and the product is finished except for filling the holes in its bottom 42 left by withdrawal of the tubular members 28. This is easily done manually, as will be explained. In the meantime, the core and jacket may be used over and over with other pallets to form additional products and the jacket and core are thus not tied up while the product cures etc.

In the ensuing description, as well as with respect to what has gone before, it is not necessary that the structure be cylindrical or even symmetrical, because it is known to form shapes other than cylindrical or even as part cylinders and part truncated cones. Hence, such terms as annular, axis" etc. are used by way of convenience and not limitation.

As best seen in FIG. 13, the pallet 20 has a plurality of openings 52, here three in number to correspond to the number of tubular members 28, it being understood that the several parts represent, broadly, a means for accomplishing the purpose. Each pallet opening 52 is of elongated or keyhole shape, whereas each tubular member is preferably cylindrical. Compare FIGS. 8 and 9. Thus the cross-sectional area of each pallet opening 52 is less than that of the interior of its matching member 28 so that, when the core is positioned over the pallet, each member 28 seats on the pallet and the bordering portions of the pallet around the openings or slots 52 project radially inwardly of the members 28 and the respective round holes 54 in the bottom of the core. When the core is released from the pallet and withdrawn upwardly (FIG. 7), the members 28 leave corresponding openings 56 later filled with additional concrete as at 60. Because of the differences in sizes and shapes of the openings 52 and 54, the disks are readily supported without dropping through.

The lock means according to the form of the invention disclosed here includes a plurality of upright rotatable shafts 62 journaled in the core bottom by means of bearings 64 (FIG. 16). Here, as elsewhere throughout the structure, the components are preferably secured together by welding, but this is deemed a matter not requiring elaboration. I

Each shaft 62 carries rigidly thereon at its lower end a lock arm 66 which, in its releasing position, passes freely through its associated pallet slot 52 so that, when turned (FIG. 17), it engages the pallet from below, thus locking the pallet and core together. As a means for operating all three shafts in unison, they are interconnected by an endless means such as a chain 68 trained about sprockets 70 keyed respectively to the shafts (FIG. 14). One of the shafts may be extended upwardly through the top of the core and provided with a squared or like upper end 72 adapted to receive a tool for turning same. A further bearing 74 is provided in the core top (FIG. 18). The lock and release positions of at least one lock arm 66 may be established by stops 78 and 80 welded to the bottom of the pallet (FIG. 17).

As previously described, the introduction of concrete into the assembled form (FIG. 4) is accompanied by a tendency to trap air in the space 30, but this entrapment is avoided by the provision of a vent opening 82 in the core bottom adapted to be closed by a swinging door or gate 84 controlled by an upright shaft 86. The gate is shown open in FIGS. 14 and 15 but is swingable to a closed position to cover the opening 82, the gate passing under a lug 88 to prevent displacement of the gate. The top of the core may be closed except for an opening (not shown) through which an attendant may observe the approach of concrete into the area of the opening 82, after which he will close the gate and prevent concrete from entering the interior of the core. Like the shaft 62 for operating the lock means, the shaft 86 may be suitably extended to the top of the core for convenience.

In order that the core may be relatively accurately centered on the pallet, the pallet openings and lock means shafts cooperate in such a fashion that each shaft bears within the smaller part of its opening 52 at 90 (FIGS. 11 and 16). Because each opening 52 is essentially on a radius, there is no displacement should the pallet and core tend to turn angularly with respect to each other.

By way of recapitulation: When the core 26 is being lowered into position relative to the pallet and cage 22 (FIG. 2), the vent 82 is open and the operating means 72 has positioned the lock arms 66 in their release or retracted positions (FIGS. 11 and 16). After the lower ends of the tubular members 28 seat on or abut the top of the pallet 20 and the lock arms 66 are beneath the pallet, the operating means 72 is actuated to turn the arms 66 to the locking positions indicated in dotted lines in FIG. 17, preferably an angle of 180. The core and pallet are now locked together and the assembly may be lowered into the jacket (FIG. 3).

As the concrete is being poured (FIG. 4), the vent 82 is controlled as aforesaid, and the assembly remains locked together through the stripping-from-the-jacket operation (FIG. 6). When the core is ready to be stripped from the finished product (FIG. 7), the lock arms 66 are turned to their release or retracted positions and the core is moved upwardly, leaving the product in place on the pallet 20, after which the pallet holes 52 are closed by the disks 58 (FIG. 12) and the manhole openings 56 are filled at 60 (also FIG. 12). Ultimately, the means 50 and header 46 are removed and the manhole is complete. In the present case it will have an opening (not shown) in its annular wall because of the ring 24. It should be observed that before the core is stripped from the finished product, the vent 82 should be opened so as to prevent the creation of a suction within the assembly that would interfere with withdrawal of the core.

I claim:

1. Apparatus for the manufacture of concrete manhole bases and the like, comprising a jacket having a peripheral wall adapted to be supported in an upright position, a horizontal pallet tolerably fitting within the jacket and supported adjacent to the bottom of the jacket and having an opening therein, a core loosely received within the jacket and having a bottom and an upright peripheral wall and located within the jacket so as to afford a peripheral space between the core and jacket walls, hollow spacer means fixed to and depending from the core bottom into the pallet opening and disposed between the core bottom and pallet and spacing said core bottom above the pallet to afford a bottom space in communication with the peripheral space, and releasable extending means from the interior of the core and through the spacer means and pallet opening and engaging the pallet for releasably locking the core to the pallet.

2. The invention defined in claim I, in which the pallet opening is smaller than the interior cross-sectional area of the tubular means.

3. The invention defined in claim 1, including operating means at least partly within the core interior and connected to and for operating the releasable means.

4. The invention defined in claim 3, including a plurality of hollow spacer means, a like plurality of releasable means, and means interconnecting the operating means and the plurality of releasable locking means for operating the latter simultaneously.

5. The invention defined in claim 4, in which each releasable means includes a shaft and an arm fixed to the shaft to engage the pallet from below, each pallet opening is of elongated shape to accommodate passage of its shaft and arm therethrough, and the operating means is connected to move the shafts angularly to turn the arms respectively out of vertical alinement with the pallet openings and beneath the pallet for locking the core to the pallet and for turning the shafts to realine the arms respectively with the pallet openings for releasing the core from the pallet.

6. The invention defined in claim Sin which each pallet opening has a bearing portion substantially closely fitting a portion of its shaft so as to cooperate with the shaft portions for centering the core within the jacket.

7. The invention defined in claim 1 including an air vent in the core bottom and movable cover means for opening and closing the vent. 

1. Apparatus for the manufacture of concrete manhole bases and the like, comprising a jacket having a peripheral wall adapted to be supported in an upright position, a horizontal pallet tolerably fitting within the jacket and supported adjacent to the bottom of the jacket and having an opening therein, a core loosely received within the jacket and having a bottom and an upright peripheral wall and located within the jacket so as to afford a peripheral space between the core and jacket walls, hollow spacer means fixed to and depending from the core bottom into the pallet opening and disposed between the core bottom and pallet and spacing said core bottom above the pallet to afford a bottom space in communication with the peripheral space, and releasable extending means from the interior of the core and through the spacer means and pallet opening and engaging the pallet for releasably locking the core to the pallet.
 2. The invention defined in claim 1, in which the pallet opening is smaller than the interior cross-sectional area of the tubular means.
 3. The invention defined in claim 1, including operating means at least partly within the core interior and connected to and for operating the releasable means.
 4. The invention defined in claim 3, including a plurality of hollow spacer means, a like plurality of releasable means, and means interconnecting the operating means and the plurality of releasable locking means for operating the latter simultaneously.
 5. The invention defined in claim 4, in which each releasable means includes a shaft and an arm fixed to the shaft to engage the pallet from below, each pallet opening is of elongated shape to accommodate passage of its shaft and arm therethrough, and the operating means is connected to move the shafts angularly to turn the arms respectively out of vertical alinement with the pallet openings and beneath the pallet for locking the core to the pallet and for turning the shafts to realine the arms respectively with the pallet openings for releasing the core from the pallet.
 6. The invention defined in claim 5 in which each pallet opening has a bearing portion substantially closely fitting a portion of its shaft so as to cooperate with the shaft portions for centering the core within the jacket.
 7. The invention defined in claim 1 including an air vent in the core bottom and movable cover means for opening and closing the vent. 